Hydraulic valve gear



Nov. 28, i933. G. W. LAMPMAN HYDRAULIC VALVE GEAR Filed June ll, 1932.

Patentedi Nov. 28, 1933 Nirao STAT RAULIC VALVE GEAR Application .luneIl, i932. Serial No. 616,58l

6 laims. (Cl. 3123-96) This invention is an improvement upon the typeofhydraulic `slack adjuster described and claimed in Patent No. 1,784,767,granted to C. E. Summers on December 9, 1930. v

5 In the application of this type of slack adjuster to V-type engines inwhich the valves are horizontally mounted and are actuated by rockerarms engaged by the camshaft the Summers design is not entirelysatisfactory for with the cylinders 10 horizontally arranged oil wouldleak past the pistons when the engine stood idle rendering the enginenoisy at starting. To overcome this objection, I have arranged thecylinders at a downward inclination. This not onlyremoves the gravityhead and retains the oil, but also permits the air to readily escape inthe form of an emulsion working between the piston and cylinder.

Another improvement consists in the provision of means to prevent theentrance of oil into the cylinder. This is accomplished by connectingthe oil supply to the cylinder at a point within the stroke-of thepiston so that an oil seal is provided about the piston effectivelypreventing the admission of air.

Other objects of the invention will be pointed out in the course of thefollowing description:

Figure l is a fragmentary View of an automobile engine having myimproved hydraulic valve mechanism applied to it.

Figure 2 is an enlarged view, partly in section, of one of the rockerarms in which my invention is embodied.

Figure 3 is an end View, partly in section, of

the rocker arm of Figure 2.

Figure 4 illustrates a slight modification.

Figure 5 shows the application of my invention to a reciprocating valvetappet.

Figure 6 shows a modification yof the design of Figure 5.

At l0 I have shown a portion of an internal combustion engine of knowntype provided with, horizontally extending valves 12 held on their seatsby springs 14. The valves are actuated .by tappets 16 pivotedfon ahollow rocker shaft 18 supplied with oil from the pressure lubricatingsystem of the engine. The rockerscarry rollers at the lower endsactuated by cams on the camshaft 20.

The pivot shaft 18 is provided with the duct 22 through which oil maypass from the hollow rocker shaft into the passage 24 provided in thehollow rocker arm. It `will be vnoted that the passage -24 extends in asubstantially vertical direction, and at its upper end communicates witha downwardly inclined bore 26 which serves as a separating or settlingchamber. The rocker is also provided with a bore 28 parallel with thebore 26. For convenience in manufacture the lower ends of the bores 26and 28 are closed by plugs 30 and 32, respectively, but other methods 60of forming may beemployed, if desired. In the plug 32 are formedpassages 34 which are in communication with the lower end of the bore 26as l shown. In the passage 34 isprovided a check valve 36 held inposition yby a suitable stop 38 and 65 resting upon a conical seat whenin closed position. Within the bore 28 is slidably mounted the piston 40which is restrained from both rotation and expulsion from the chamber bypin 42 passl ing through the walls of the cylinder and through 7U? aslot formed in the piston. A passage 44 establishes communicationbetween the slot in the piston and the upper endof thepassage 24.

In the operation of the device oil from the en`- gine lubricating systempasses from the interior i5 of the pivot shaft 18, through passages 22,24,

26 and 34, and past ball check valve 36 into the cylinder forcing thepiston 40 outwardly so that it engages the'end ofthe valve stem. Thisoperation, of course, can only take place when the 8@ valve 12 is on itsseat, and the system thereby relieved from the pressure of the spring14. When the cam begins to rock the rocker 16 the check g. valve 36 isimmediately seated by the pressure of the piston 40 on the oil, and theoil acts as 85 a rigid abutment or seat for the piston 40 causing it toforce the valve off its seat. This action continues until the rollersagain engage the base circle of the cam, and the valve is seated. Theoil pressure is then again effective to raise 9@ the valve 36, andsupply the deficiency of oil which may have been produced by leakagepast the piston 40.

Not only is oil supplied to the cylinder 28 through the passage 34 butthrough the passage 95 44 the oil pump pressure is applied to theperiphf ery of the piston 40 producing an oil seal which preventspassage of air into the cylinder. It will be noted also that any airthat may have come with the 011 into the bore 26 win naturally gravi-100 tate upwardly into passage 44, and be forced out between the pistonand its cylinder. The up- -ward inclination of the bore 28 likewisefacilitates the escape of entrained air between the cylinderv and pistonin the form of an emulsion. As a result of the inclined arrangement ofthe bores 26 and 28, and the fact that their connection with Ythe oilsupply is above the lower end of the piston, the hydraulic chamberbeneath the piston will remain filled with oil however los' oil supplyfail however, the engine will operate although noisily by engagement ofthe plug 32 with piston 40.

In Figure 4 I have shown a slight modification. Here the piston 40 isprovided with an annular groove 50 in addition to the notch to receivethe pin 42 which holds the piston against rotation and expulsion'fromthe cylinder., In this construction, also, the drilled passages aresomewhat differently arranged. Attention is particularly called t0 thepassage 52 closed by a screw plug 54. Within this passage there isprovided the plug 56 carrying the ball check valve as before. Thepassage 52 communicates with the cylinder containing the piston, asindicated at 58. This arrangement simplies manufacture somewhat in thatthe machining of the plug 56 is simpler than the machining of plug 32.However, the hydraulic chamber is somewhat enlarged, and this may leadto slightly more trouble with air.

v In Figure 5 I have shown the application of my invention to aconventional form of tappet. Here the oil supply comes through passage60, and is fed by suitable passages'to the bores 26' and 28'. 'Ihetappet 70 is in the form of a cylinder in which is slidably mounted thepiston 72 engaging' the end of the .valve stem '74. Oil is supplied tothe cylinder '70 through passages V34 which may either continuously orintermittently align with passage 76'. Here the passage 26 likewise actsas a settling chamber, and also provides a head of fluid to keep thehydraulic chamber filled atv all times.

In Figure 6 I have shown a further modification. Here the piston 78 isslidably mounted in tappet 80. Oil' is fed to the space between thepiston and tappet from passage 82 through communicating passages in thewalls of the tappet and piston, as shown, to the passage 84 extendingcentrally through the piston. The lower portion of the passage 84 isenlarged, as shown, and contains a spring 86 yieldingly holding ballcheck valve 88 on its seat. The advantage of this construction residesin the fact that foreign matter tending to lodge between the valve 88and its seat will be forced out of place by the entering oil stream, andwill settle down to the bottom of the tappet where it will not interferewith operation.

I claim:

1A. In a valve slack adjuster the combination of a cylinder, a piston inthe cylinder adapted to engage a part of the valve gear, a source ofsupply of oil under pressure, a passage outside of long the engine maystand unused. Should thesaid cylinder and piston leading from saidsource to the cylinder below said piston, a non return valve in 'saidpassage, a passage leading from said source to the piston above itsplane of contact with the liquid to prevent the passage of air into thecylinder and a channel connecting said passages so that air entrainedwith the liquid is delivered to the second named passage.

2. In a valve slack adjuster, the combination of a rocker arm having ahollow hub adapted to be connected with a source of oil under pressure,said rocker arm being formed to provide a cylinder, a piston in thecylinder, a passage outside of said cylinder and piston leading fromsaid hub to said cylinder adjacent its lower end, a non-return valveinsaid passage, a piston in the upper portion of the cylinder, a passageconnecting said hub with the upper portion of the cylinder to preventthe passage of air into the cylinder.

3. In a valve slack adjuster, the combination of a rocker arm having ahollow hub adapted to be connected with a source of oil under pressure,said rocker arm being formed to provide a cylinder, a piston in thecylinder, a passage outside of said cylinder and piston leading fromsaid hub to said cylinder adjacent its lower end, a nonreturn valve insaid passage, a piston in the upper portion of the cylinder, a passageconnecting said hub with the up'per portion of the cylinder to preventthe passage of air into the cylinder a passage connecting saidfirst-named passages so that entrained air will be discharged throughsaid second-named passage.

4. A valve rocker arm having a pivot receiving bore and a pair ofsubstantially parallel bores extending at an angle tothe rst named bore,a passage connecting said pivotal bore with one of said parallel bores,a piston in the other of said parallel bores, passages connecting saidparallel bores adjacent the tops and bottoms thereof, a non-return valvein the lowermost passage.

5. The combination of a substantially horizontal reciprocating part, amovable member having a downwardly inclined bore therein, a piston insaid bore engaging said reciprocating part, and a body of iluid in saidbore, the inclination of said bore preventing escape of said fluid byaction of gravity.

6. In a valve operating mechanism, the combination of a substantiallyhorizontal reciprocating actuated part, a rocker for actuating said parthaving a downwardly inclined bore therein, a piston in 'said boreengaging said actuated part, and a body of fluid in said bore, theinclination thereof preventing escape of uid by action of gravity.

GEORGE W. LAMPMAN.

